Having had both sized early zolatone marins either would work for you. I’m 5ft 9 and actually prefer the smaller size. More top tube clearance. The pic below was of my team Marin which was the same size and the seat tube was set up for the correct height.Hello - thanks for your question. It is a 15.5inch frame. I'm 5'9, its ok for me, but generally speaking for my height a 17.5 inch is more desirable.